The present invention relates to a spot-type floating-caliper disc brake with at least one guide bolt secured to the brake support member and extending from the brake support member into an axial bore of the brake caliper provided at the side of the brake cylinder, with means being arranged at the guide bolt to restore the floating caliper after a braking action.
In a known spot-type floating-caliper disc brake, such as disclosed in British Pat. No. 1,255,079, the floating caliper is guided axially at two guide bolts secured to the brake support member. To displace the floating caliper away from the brake disc in its guide for detachment of the brake shoe which is actuated directly by the floating caliper, the known brake includes elastic rubber rings in the brake support member which embrace frictionally the guide bolts secured to the brake caliper. When the brake is applied, the rubber rings will be deformed elastically so that they tend to shift the floating caliper into its initial position again after the brake is released. However, in practical operation, this construction will not achieve the effect desired. The friction force attainable between the guide bolts and the rubber rings is too small to overcome the resistance in the floating-caliper guide. In addition, the travel of elastic deformation is insufficient to conform to the actuating travel of the floating caliper which varies dependent upon the magnitude of the actuating force. That is to say, employment of this restoring alternative in a floating-caliper disc brake having guide bolts which are fixed to the brake support member as disclosed in German Patent DE-OS No. 2,840,374 would not solve the problem of restoring the brake shoe that is fastened directly to the floating caliper after a braking action.